The present invention relates generally to the field of athletic and exercise equipment. More particularly, this invention relates to the field of devices and methods for assisting individuals with performing weight lifting exercises in order to prevent injury and to increase the effectiveness of the exercise.
A significant problem for free weight lifters is that, in the absence of a human spotter, it is difficult to derive the maximum benefits from lifting the weights. The reason is that it is dangerous to continue an exercise to the point of fatigue, which is the very time when maximum benefit is derived. In other words, the lifter lifting alone must stop lifting when any doubt creeps into his or her mind whether they can perform the next repetition. In lifts where the bar would not be a danger to the lifter if he or she could not do an extra repetition, such as a curl, the lifter still does not derive maximum benefit from the exercise because of the lack of a spotter. Doing bench presses, where the weight lifter lays underneath the free weights, is particularly dangerous without a spotter.
The prior art includes the following United States Patents: Tanski, U.S. Pat. No. 4,807,875; Ryan, U.S. Pat. No. 5,048,826; and Coleman, U.S. Pat. No. 5,407,403. The apparatus disclosed in the ""875 patent issued to Tanski has two arms that extend from the sides of a bench press device. These two arms extend underneath an Olympic weight lifting bar. A chain and sprocket assembly, driven by an electric motor, raises and lowers these arms. This device is operated by a switch positioned at the foot of the athlete. In addition, the device is provided with switches that limit the raising and lowering of the arms.
A safety apparatus for use with a barbell assembly is taught by the ""826 patent issued to Ryan. This assembly includes a support frame, a pair of cables that extend to engage the barbell, and a winch assembly on the support frame that extends and retracts the cables. In addition, the device is provided with sensors to measure the tension on the cables. Also, the device has sensors to measure the direction and the velocity of the movement of the cable. A controller, such as an Intel 8087 micro-controller, is used to control the operation of the winch assembly.
The ""403 patent issued Coleman teaches a weight lifting safety device that has a computerized control system. This device contains a motor driven cable and a sprocket assembly that can be connected to either a barbell or a pair of dumbbells. The device is provided with sensors to track the speed of the motion of the cable. The control system is programmed with the desired velocity profile of the motion of the bar for the exercise. If the weightlifter moves at a pace that is faster or slower than this profile, the control system activates the motor driven cable assembly and takes control of the weight.
The following electro-mechanical device has a frame which supports two arms, called spotter arms. The two spotter arms extend out so as to be able to support a barbell. The arms raise and lower on the frame, remaining parallel with the floor and perpendicular to the frame. Thus, this device provides a free weight lifter with assistance in lifting weights when, during the course of the exercise, the muscles are fatigued and the lifter cannot lift the amount of weight on the bar by themselves. This assistance is called a xe2x80x9cspot.xe2x80x9d A control system operates the movement of the two spotter arms. The movement of these two spotter arms is caused by a motor-driven lead-screw. This electro-mechanical device is provided with an electro-optical sensor that provides feed-back information to the control system.